Rechargeable battery powered devices are ubiquitous and used in many applications where high reliability is desired. For example, some modern inventory systems employ battery-powered mobile drive units that transport inventory holders within an inventory facility. Each mobile drive unit typically includes a battery that is recharged repeatedly over time. Reliable operation of such an inventory system depends on reliable operation of the mobile drive units. Reliable operation of the mobile drive units depends on reliable functioning of the rechargeable battery of the mobile drive unit. Rechargeable batteries, however, typically degrade over time and, if not replaced in a timely fashion, may fail and thereby detrimentally impact the reliability of the respective device and/or system in which the rechargeable battery is employed.